TP 13029
- Not Recommended
- Limited Recommendation
- Highly Recommended
- Habitat Modification
- Active Bird Control
- Conclusion
Bird control products can be categorized by the manner in which they deter or disperse birds - novelty avoidance, startle reaction, predator mimics, warning signals, and killing (Rochard 1996). Many of the least effective products/techniques are based on the presentation of novel stimuli and/or stimuli that startle birds by the suddenness or loudness of their presentation. Birds tend to avoid any novel stimulus, such as the synthetic sounds produced electronically by the Phoenix Wailer, because birds do not know whether this is a threat or not. This has obvious survival value. (Some birds may initially investigate, rather than avoid, a novel stimulus.) Once the stimulus is no longer novel, however (and birds quickly learn what is a threat and what is not), the stimulus has lost its effectiveness on those birds. Similarly, "startle" devices (e.g., gas cannons) lose their effectiveness once they become an expected part of the birds' environment and no longer startle. Although there is a biological basis to these products, any deterrent/dispersal effects are short-lived.
The biological basis behind bird control products/techniques that mimic known threats to birds, such as scarecrows and hawk kites, tends to be stronger and longer-lived. The period of effectiveness is related directly to the realism of the model – in appearance, behaviour, and sound. Birds will quickly habituate to a "Canadian Tire" owl. They will habituate more slowly to a stuffed owl with a crow in its talons that moves and calls. A real owl tethered to a post works even better. Even with the best models, unless the presentation is occasionally supplemented (with killing, for example), birds eventually learn that there is no real threat. Similarly, stimuli that communicate a "warning signal" to the target bird that a predator is nearby (e.g., distress/alarm calls), or has been in the vicinity (e.g., model of dead prey bird), work well. Habituation does not readily occur.
Killing birds in and of itself generally is of immediate or short-term use only. In conjunction with other products/techniques, killing can be a very effective supplementary technique.
Airport bird control has some specific requirements that differ from other bird control situations, such as control in agricultural settings. Ability to control where and when birds are dispersed is important. A potential bird hazard is created rather than removed if birds are flushed across an active runway, for example. The most critical requirement, however, is the need for an airport bird control program to be effective over the long-term. In agricultural situations, deterring birds until a ripening crop is harvested is sufficient. At airports, bird hazards can be present 12 months of the year, and even 24 hours of the day. Given this, habituation to products/techniques by birds becomes a major concern. Birds will habituate more quickly to control devices that have a weak biological basis and little variety of presentation.
We sorted the bird control products and techniques reviewed in this report into three broad categories: (1) Not Recommended, (2) Limited Recommendation, and (3) Highly Recommended. This evaluation was based on the answers to three key questions. (1) Is there a sound biological reason to expect the product/technique to work? (2) How quickly and to what degree do birds habituate to the product/technique? (3) Are cost and practicalities of implementation a consideration?
Nine products/techniques are Not Recommended. The use of High Intensity Sound, Microwaves, and Lasers are not recommended because the energy levels required are dangerous to humans (and birds and other mammals). Very few species of birds have been shown to detect Ultrasound, and those that can have not shown an avoidance reaction. Aircraft Hazing and the use of Smoke are not recommended because they are impractical for use on airfields. Insufficient research has been conducted on the use of Magnets, Lights, Dyes, Aircraft Engine Noise, Infrasound for bird control; however, the research to date does not suggest that these products are strong candidates for airport bird control.
The majority of the bird control products/techniques reviewed here fall into the "okay, but..." category. They can repel or disperse birds but they are limited in their effectiveness because of habituation, weak biological basis, limited application, and/or implementation problems. These products work best when part of an integrated program, and should not be considered individually as key components of a control program. They may, in some circumstances, be useful tools to have in your bird control "toolbox".
This repellents. Birds tend to habituate relatively quickly to Gas Cannons and, we expect, to the similar "Falcon-Imitator" and "Rotating Hunter" units from Agri-SX as well, although there has been little testing of the last two products. The use of remotely-fired gas cannons may extend the period of their pre-habituation usefulness.
The distress/alarm calls of the Phoenix Wailer are likely to be more effective than the ultrasounds and synthetic electronic noises also broadcast by these units. Similarly, the synthetic noises produced by the AV-Alarm have no biological basis beyond novelty and startle avoidance reactions, which are susceptible to quick habituation. Bird Gard AVA and Bird Gard ABC are distress call players that offer small repertoires of distress/alarm calls of a limited number of species.
Most visual deterrents also are susceptible to habituation - Scarecrows, Reflecting Tape, Predator Models, Hawk Kites and Balloons, and Gull Models. Chemical repellents – Tactile, Behavioural, ReJeX-iT, and those for control of earthworms (Benomyl, Tersan, and Terraclor) – can be effective but only for specific limited applications. Other taste aversives besides ReJeX-iT are unproven. Foam, playbacks of Predator Calls, and Lure Areas have potential for bird control in certain situations but have been inadequately tested. Trapping and Surfactants and Water Spray are suitable for limited applications.
Model Aircraft can be successful for bird control but they are very labour intensive and they cannot be used near active runways and taxiways at the airport.
The most important aspect of a successful airport bird control is that it must be designed for the specific problems at that airport. It is important to gain an understanding of the numbers and species of birds at the airport and to determine those species and times that create the greatest threat to aircraft safety. The bird control program should then be focussed on the identified high priority species and times.
A handful of products/techniques are Highly Recommended. These can be considered core elements of an effective airport bird control program. They provide long-term control, with little habituation if implemented correctly; the active approaches require the frequent involvement of skilled, motivated staff.
The best passive technique for long-term bird control at airports is Habitat Modification. This addresses the root cause of bird problems by modifying the habitat at the airport that is attracting the entire annual cycle of bird presence (i.e., wintering, nesting, and migration). This study should identify the species that create bird hazards and how they use the airfield and other airport and adjacent facilities. Modify the habitat to remove or alter those features that attract the most problematic species. It is important to insure that the new habitat will attract only species that pose a smaller hazard to aircraft safety. This is necessary since it is not possible to make the habitat unsuitable for all species.
The second component of habitat management is to install, where feasible, physical barriers such as Fencing, Netting, and Overhead Wires and Lines to exclude birds from identified critical areas at the airport. Bird Balls could be used to cover ponds. Physical barriers permanently exclude birds from treated areas, but they must be maintained and monitored. The use of perch barriers such Nixalite, Bird-B-Gone, Avi-Away, and Fine Wires on buildings, signs, and airport light fixtures may also be appropriate.
Habitat Modification will have reduced the numbers of problem species attracted to the airport. However, other hazardous species will inevitably still be present. An active control program will be necessary to eliminate these species. Techniques that should be key components of an airport active bird control program are Pyrotechnics, Falconry, Distress and Alarm Calls, and Shooting. These could be supplemented with selected techniques from the previous section (Limited Recommendation). For example, the use of gull models (stuffed specimens) to supplement pyrotechnics can be effective at reinforcing the concept that the pyrotechnics might be dangerous to the bird's health. Falconry use at airports is somewhat controversial. It can be a useful technique if properly implemented. Falconry is not appropriate at all airports.
One theme dominates our analyses of the many techniques for airport bird control. That is, none of the techniques that have been evaluated will work consistently over the long term unless they are applied properly by appropriately trained personnel. This point cannot be overemphasized! There are no single magic solutions for bird control. All successful programs have a biological basis and are operated by well-trained staff. If any significant bird hazard problems exist at an airport, then a full-time staff is likely to be needed.
Operation of a successful airport bird control program requires a major commitment from airport management to insure that adequate funding is in place and that bird control is seen as a high priority activity to insure aircraft safety.